Abstract

This paper describes the design and construction of a local six-electrode conductivity probe which can be used in solids-water pipe flows to simultaneously measure the local solids volume fraction and the local solids axial velocity. Using finite element analysis, the probe electrode geometry was designed so that the regions of the solids-water mixture that were interrogated by the probe were optimal for measurement of the volume fraction and for cross correlation velocity measurement. The probe was used, in conjunction with a computer controlled traversing mechanism, to obtain distributions of the local solids volume fraction and the local solids axial velocity both in vertical upward and in upward inclined solids-water flows. Such distributions can be used to validate volume fraction and velocity profiles obtained using dual-plane electrical resistance tomography systems. Experimental results indicated that the six-electrode probe can be used to estimate the local solids volume fraction in vertical upward solids-water flows with a mean absolute error of approximately 0.01. Experimental results also indicated that the six-electrode probe can be used to measure the local axial solids velocity with a mean error of 2% of the reading.